Xenoterra is a Freeware Windows-Compatible BBS system with hooks for
both dial-in and TCP/IP connections.

I was able to find mentions of work on Xenoterra by Spellweaver as early
as 1996. Work was done on a API for doors for Xenoterra as well. The
version in this entry is a 1.00 beta released on 1999 and is the only
available copy. The website for Xenoterra includes information that a
further release is due in 2004; considering the software is first mentioned
in May of 1996, a release happens in 1999, and the next possibility of
a release if five years later, the schedule for this software is slow
indeed.